Umbraco should drop support of static access to logger

[bielu]

With umbraco v9, umbraco started using Microsoft.Extensions.Logging.Abstractions, which is great as allows to swap logger to any logging solution, not just serilog. but when reviewing code I noticed multiple cases of accesing serilog through static accessor, which means we are tied to specific implementation.

I tried to figure out why it was done, but I would assume it is left over from v8, as not seeing any reason for it in v9+.